Spin Seebeck Effect from Antiferromagnetic Magnons and Critical Spin Fluctuations in Epitaxial FeF2 Films
Spin Seebeck Effect from Antiferromagnetic Magnons and Critical Spin Fluctuations in Epitaxial FeF2 Films
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DOI：
10.1103/physrevlett.122.217204
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发表时间：
2019-05-31
影响因子：
8.6
通讯作者：
Shi, Jing
中科院分区：
文献类型：
--
作者：
Li, Junxue;Shi, Zhong;Shi, Jing
我们报告了外延生长的 FeF2 (110) 反铁磁 (AFM) 薄膜的纵向自旋塞贝克效应 (SSE) 研究，该薄膜在 3.8-250 K 的温度范围内具有强单轴各向异性。FeF2 薄膜的尼尔温度 (T-N = 70 K) 以下的磁场和温度相关的 SSE 信号与基于 AFM 磁振子激发的理论模型一致，没有任何净感生静电磁矩。除了与 AFM 磁振子相关的特征低温 SSE 峰外，T-N 处还有另一个 SSE 峰，该峰很好地延伸到顺磁相。在临界点 T-N 附近和上方的不同磁场（高达 12 T）下采集的所有 SSE 数据都很好地遵循临界标度定律以及 3D Ising 系统磁化率的临界指数，这表明 AFM 自旋相关性是观察到 T-N 附近的 SSE 的原因。
We report a longitudinal spin Seebeck effect (SSE) study in epitaxially grown FeF2 (110) antiferromagnetic (AFM) thin films with strong uniaxial anisotropy over the temperature range of 3.8-250 K. Both the magnetic-field and temperature-dependent SSE signals below the Neel temperature (T-N = 70 K) of the FeF2 films are consistent with a theoretical model based on the excitations of AFM magnons without any net induced static magnetic moment. In addition to the characteristic low-temperature SSE peak associated with the AFM magnons, there is another SSE peak at T-N which extends well into the paramagnetic phase. All the SSE data taken at different magnetic fields up to 12 T near and above the critical point T-N follow the critical scaling law very well with the critical exponents for magnetic susceptibility of 3D Ising systems, which suggests that the AFM spin correlation is responsible for the observed SSE near T-N.